Earth

The third planet from the Sun and the only known place in the Universe where life exists.

71% of the planet is covered in liquid water, this has become crucial for life. It is known as "Goldilock's Planet" because it is not too hot that the water boils away, and not too cold that the water freezes.

The land masses (as well as the oceans) are sitting on top of tectonic plates. The crust of the Earth is cracked like an egg and each section is called a tectonic plate. These plates move around causing earthquakes. At the places where they join, volcanoes form. These areas are called fault lines.

The atmosphere is made up of 78.1% Nitrogen and 20.9% Oxygen. The other 1% is made up of water vapour and other gases like Carbon Dioxide.

Carbon Dioxide has been found to play a big role in the Greenhouse Effect. Scientists suggest that Carbon Dioxide levels have been increasing which can lead to an increase in "Global Warming". A combination of increased population and deforestation is thought to be the main cause. There are many sceptics to this theory.

The atmosphere is very active. Powered by the Sun, it is constantly moving around creating weather systems. The Earth is tilted at 23.5 degrees, this means some times of the year, one hemisphere is pointing closer to the Sun than the other, this effects the atmosphere and therefore the weather systems, which gives us seasons.

The Earth has a magnetic field. This is generated from the core of swirling molten iron. This field protects the Earth from Solar Winds. Currently, the North magnetic pole is in the Arctic, and the south one in is in Antarctica. There is evidence that suggests that these have switched throughout history. If this happened today, the result would be catastrophic.

Taken by Moderate Resolution Imaging Spectroradiometer, on NASA's Terra satellite.

This picture portrays just how much water is on out planet.

Credit: NASA.

This image is the most spectacular and detailed image of our planet to date.

Different sensors of different instruments were pooled together to gather the different components of the picture. In the Credit below, you can see what was involved.

It shows what the different regions look like at night. You can clearly make out individual cities. Looking closer at those cities and you would be able to make out landmarks (see night picture of London.

Credit: NASA

This picture was taken by the crew aboard the International Space Station on February 4th 2003. What looks like a cluster of stars is actually London.

Around the edges you can see the M25 motorway as well as Gatwick and Heathrow airports (labelled).

In the just west of the dense city centre you can see the dark regions of Hyde Park and Regents park.

The hazyness on the outskirts was caused by low cloud or fog.

Credit: NASA

One of a series of photos taken from Galileo during it's fly-by in December 1990.

The image appears to be natural colour but is in fact not. It is made up of colourized versions of green, red and infra-red filters.

This was done so that the land features would be more distinguished than the atmosphere and ocean features.

Credit: NASA

This is a mosaic of 40 photos of Antarctica taken from Galileo in December 1990.

You can see three oceans surrounding the continent Pacific to the lower right, the Indian to the upper right, and a small section of the
Atlantic at the upper left.

The faint blue line along the bottom, marks the atmosphere.

Credit: NASA

This map shows the main tectonic plates on Earth.

These are constantly shifting because of currents in the mantle under the crust.